Typhlocarcinops ocularius Rathbun, 1914

Ng, Peter K. L. & Rahayu, Dwi Listyo, 2020, A synopsis of Typhlocarcinops Rathbun, 1909 (Crustacea: Decapoda: Brachyura: Pilumnidae), with descriptions of nine new species from the Indo-West Pacific, Zootaxa 4788 (1), pp. 1-100 : 55-57

Typhlocarcinops ocularius Rathbun, 1914

( Figs. 45 , 46 )

Typhlocarcinops ocularia Rathbun, 1914: 153 ; Tesch 1918: 212; Yokoya 1933: 201; Sakai 1939: 572; 1976: 547, text figs. 294a, b; Dai et al. 1986: 385, text fig. 203(1–3), pl. 56(2); Dai & Yang 1991: 414, text fig. 203(1–3), pl. 56(2).

Typhlocarcinops ocularius — Ng et al. 2008: 144.

Material examined. Holotype: male (17.0 × 13.5 mm) ( USNM 46408 ), station 5392, Destacado Island , between Samar and Masbate, Philippines, 243 m, coll. RV Albatross, 13 March 1909.

Diagnosis. Carapace ( Fig. 45A, B ) about 1.3 times broader than long, surface with granules anteriorly, posteriorly, regions not indicated; anterolateral margin arcuate, lined with tiny granules, entire. Front ( Fig. 45B, C ) bilobed, with shallow median cleft, margin of each lobe slightly convex. Orbit ( Fig. 45B, C ) short, bulbous ocular peduncles filling orbit, immovable, cornea small, pigmented. Epistome ( Fig. 45C ) relatively broad, concave. Antennal peduncles relatively long. Third maxilliped ( Fig. 45D ) with merus broad, squarish, outer and inner margins straight, ischium as broad as and, longer than merus, inner margin slightly shorter than outer margin, lower margin slightly oblique; exopod relatively stout, tip reaching to just before distal edge of merus, inner margin with distinct tooth. Chelipeds unequal ( Fig. 45A, G, H ), major chela smooth, shiny, minor chela with some tubercles and setae on lower margin; outer surface of fingers with longitudinal ridge on dactylus and fixed finger, continue to palm; cutting edges of fingers with prominent teeth; inner angle of carpus with short spine ( Fig. 45A ). P2−P5 ( Fig. 45A ) proportionally long, fringe by sparse long setae on dorsal and ventral margins; merus of P5 not reaching front when folded. Fused thoracic sternites 1, 2 broadly triangular ( Fig. 45E, F ), proportionally broad; thoracic sternites 3, 4 partially fused, with only lateral suture discernible. Male pleon ( Fig. 45E, F ) relatively narrow, telson long, 1.8 times as long as somite 6, subtriangular with rounded distal margin. G1 ( Fig. 46 ) slender, upper half longer than lower half, slightly curved, distal part directed upwards with pointed tip. Female not known.

Remarks. This species was described from one male collected from the central Philippines. Yokoya (1933: 201) reported “ Typhrocarcinops ocularia Rathbun, 1914 ” on the basis of five males and four females from the prefectures of Yamaguchi and Shimane in Japan but did not elaborate, even though at that time, no one had figured that species. Yokoya (1933) also did not provide any figures or description. Sakai (1939, 1976) accepted Yokoya’s (1933) record of the species from Japan without comment. Takeda & Miyake (1968: 571) identified four males and a female from the East China Sea as T. ocularius , described the species and figured the G1; but Sakai (1976: 547) commented that their specimens probably belonged to T. decrescens . This present study considers that the record of Takeda & Miyake’s (1968) should be referred to T. denticarpes . Sakai (1976: 547, text-fig. 294a, b) did not examine specimens of this species from Japan but figured the type of T. ocularia from the Philippines. The G1 figures provided by Takeda & Miyake (1968: fig. 9c, d) are different from what is now known for T. ocularius s. str. and confirms Sakai’s (1976) supposition. The distal part of the G1 of Takeda & Miyake’s (1968) species, however, is bent at right angles whereas that of T. decrescens is more curved and hook-shaped ( Figs. 23 B–E, H–K, 24A–G). Takeda & Miyake’s (1968) figures compare well with T. denticarpes ( Figs. 28 , 29 C–F, H–J, 30C–F).

Dai et al. (1986) figured the type male from the Philippines and added T. ocularius to their fauna list even though, as they admitted only in the Chinese text, no specimens had been recorded from China. Dai & Yang (1991) also listed the species as part of China’s fauna but without any comment. Typhrocarcinops ocularius must be excluded from the Chinese fauna until specimens are actually found.

Type locality. Destacado Island , Philippines .

Distribution. Philippines and possibly Japan.

Figures

FIGURE 23. Typhlocarcinops decrescens Rathbun, 1914. A–E, holotype male (9.7 × 7.6 mm) (USNM 46407), Sulu Archipelago, Philippines; F–K, male (6.8 × 5.3 mm) (ZRC 2018.0269), Papua, Indonesia. A, right third maxilliped; B, H, left G1 (ventral view); C, I, left G1 (dorsal view); D, J, distal part of left G1 (ventral view); E, K, distal part of left G1 (dorsal view); F, left third maxilliped; G, male pleon. Scales: A–E, J, K = 0.5 mm; F–I = 1.0 mm.

FIGURE 28. Typhlocarcinops denticarpes Dai, Yang, Song & Chen, 1986, holotype male (15.4 × 12.0 mm), Guangdong, China. A, right G1 (ventral view); B, distal part of right G1 (ventral view); C, left G1 (ventral view, setae not drawn); D, left G1 (dorsal view, setae not drawn); E, distal part of left G1 (ventral view, setae not drawn); F, distal part of left G1 (dorsal view, setae not drawn). A, B, after Dai et al. (1986: text fig. 202(1)), incorrectly labelled as “Typhlocarcinops canaliculatus Rathbun, 1909”. Scales = 0.5 mm.

FIGURE 29. Typhlocarcinops denticarpes Dai, Yang, Song & Chen, 1986. A–F, male (11.4 × 8.6 mm) (ZRC 2018.0694), Hong Kong; G–J, male (15.9 × 12.4 mm) (ZRC 2018.0700), Hong Kong. A, left third maxilliped; B, G, male pleon; C, H, left G1 (ventral view); D, left G1 (dorsal view); E, I, distal part of left G1 (ventral view); F, J, distal part of left G1 (dorsal view). Scales: A, B, G = 1.0 mm; C–F, H–J = 0.5 mm.

FIGURE 45. Typhlocarcinops ocularius Rathbun, 1914, holotype male (17.0 × 13.5 mm) (USNM 46408), between Samar and Masbate, Philippines. A, overall habitus; B, dorsal view of carapace (right side denuded); C, frontal view of cephalothorax; D, right third maxilliped; E, anterior thoracic sternum and pleon; F, posterior thoracic sternum and pleon; G, outer view of right chela; H, outer view of left chela.

FIGURE 46. Typhlocarcinops ocularius Rathbun, 1914, holotype male (17.0 × 13.5 mm) (USNM 46408), between Samar and Masbate, Philippines. A, left G1 (ventral view); B, left G1 (dorsal view); C, distal part of left G1 (ventral view). Scales = 0.5 mm.